Almost a year ago, Porsche revealed to the world their next supercar which is the 918 Spyder. It will be a limited production model as Porsche intends to build only 918 units. The car will boast a V8 hybrid engine which generates around 718bhp with an exceptional fuel consumption of 78mpg.

Porsche will unveil a production unit of the 918 Spyder at the 2013 Frankfurt Auto Show and now, Porsche has officially revealed that there will be changes to the 918 Spyder which we can expect to see by late 2013 or early 2014. One of the key changes to the car is the engine size. The V8 engine will remain but the engine’s displacement has been increased from 3.4 litres to 4.6 litres.

The new engine will also feature a hosts of new technologies which include a central injector mounted directly adjacent to the spark plug, a central oil feed to the crankshaft, a variable-pressure composite oil pump and scavenge pump, forged lightweight pistons from a Formula 1 supplier, a very high compression ratio. Another technology which will be included and also a Porsche first; variable valve timing with intake and exhaust phase stepper motors.

Even though there are much revisions done on the engine that will be used on the car, the engine is still based on the V8 originally developed for the RS Spyder LMP2 race car which has proven itself in endurance racing.

On top of this, the new engine itself will generate around 550bhp, 50bhp more from the original concept. At first, Porsche will use three electric motors for the car. But now, Porsche will reduce the number to two. The remaining two electric motors will have a combined horsepower of 230. This will add a total of 780bhp for the car, a substantial increase from the original plans. The engine will be mated to a seven speed PDK (Porsche’s dual clutch) transmission.

Another change is the dimensions of the car. The length will increase by 5.8 inches and its width will increased by half an inch. The car will use a liquid cooled lithium-ion battery to power-up the electric motors. It can be charged through a conventional domestic type socket and it will take around 3 hours to fully recharge the motors.

With a dry weight of 1675 kilograms, the 918 Spyder will have a power to weight ratio of 2.15kg/bhp (465bhp/tonne). And, by comparison, the Lamborghini Aventador has a 2.25kg/bhp power to weight ratio. On paper, these figures do not mean much. Only time will tell what sort of performance the 918 Spyder is capable of.

@Friendstar: Yes you are right, the Aventador is already on sale. It is just that when automakers produce a certain model (especially a supercar like the 918 Spyder), people will usually try to compare it with a similar car from another maker. I also feel that Porsche themselves will benchmark their cars with other maker's cars.Anyway, I believe that the Aventador will still be around when the 918 Spyder comes out and we will definitely get to see some groups/people who will test their supercars with the 918 Spyder.